"If a person unaware of the effective potency of a certain medicine takes that medicine or is forced to take it, it will act even without his knowledge because its potency does not depend on the patient's understanding. Similarly, even though one does not know the value of chanting the holy name of the Lord, if one chants knowingly or unknowingly, the chanting will be very effective." Therefore when Ajamila, on his death bed, called out for his son Narayana, he was unknowingly chanting the holy name of the Lord. As soon as he uttered, 'Narayana', the Vishnudutas, the messengers of Lord Vishnu, came there and stopped the Yamadutas from taking the soul of Ajamila to the lord of death for judgement. The Vishnudutas then left and Ajamila was given more time on the earth. Ajamila greatly regretted his past sinful activities. He decided he must completely control his mind and senses, and he resolved to never fall again into the ignorance of material life. -Quoted portion from Srimad Bhagavatam 6.2.20